Lifting-magnet.



A. C. EASTWOOD.

LIFTING MAGNET.

APPLIOATION FILED MAY 13,1910.

978, 1 1 9. .Patented Dec. 6, 1910.

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To all whom it may concern:

1 woon, a. citizen of the United States, residing at Cleveland, in thecounty of Cuyahoga and State of Ohio,l have invented newand vusefulImprovements in. Lifting-Magnets, of which the following is aspecificationK My invention relates broadly to electromagnets, but hasspecial reference to what are termed lifting magnets, and its object ist'o construct the same so that the mag.- netizing winding may bethoroughly insulatedagainst grounding or short-circuiting vdue to thehigh inductive voltage generated in the winding'when the source ofenergy is cut off kor to other causes.

Referring to the accompanying drawing, Figure l is a perspective of aunit winding constructed in accordance with my invention; Fig. 2, acentral vertical section of Fig. 1; Fig. 3, a perspective of one of thevinsulating spacers which I -place between successive coil sections ofthewinding; and Fie. 4, a perspective of a portionof a spacer di eringfrom the construction shown on Fio.' 3.

'Io facilitate an understanding of the present invention, I refer toLetters Patent No. 928,510 granted to me July 20, 1909,

in which. Figs. land 2 show' a unit 'wind- .ing designed Afor the samepurpose as the Cstructure shown on Figs. l and 2. of the' drawing ofthis application, but it is to be understood that my invention isappli-' cable to windings designed for various uses.

and mounted and constructed in different ways from the Way shMn on thesaid Letters Patent.- In fact, it is applicable to all electro-magnetshaving'a'number of super# posed coil-sections, whether clamped togetherin units or not.

On the drawings, the bottom plate A, composed preferably of brass isprovided at its inner edge with the upstanding tubular flange or mandrela4. On thetop of the plate A, I place the unslot-ted annular insulatingspacer or plate @which supportsthe lowest winding section e. O n topof`the winding sectionf ei is the insulating spacer or plate a7 providedwith the slots or'channels 7c preferably arranged radially and extendingthrough the entire thickness of the plate al, but the slots may begrooves as. shown at l, on Fig. 4`or otherwise. `I place anotherwinding-sectione2 Ispacer or plate a on the section e2.- The windingsections is placed er1-the second plate a?, and another insulatingspacer or plate a is placed on the section e3, The Winding section e* isplaced on 'the third plate a1 andthe insulating top plate a8 is placedonthc section et Radial clamping straps s, 82,83, vfare placed over thetop-plate as and are drawn down by means of screws d and d2, the

screws d en aging with bosses in the upper'` end of the ange a4 and thebolts d2 passing through holes near the outer edge ofi"v the bottomplate A, these straps binding the winding sections, the bottom. plate,and the insulating plates into a unit winding, which may be moved" andassembled in a magnet f case Without injuryto the winding. After thisAunit has been assembled, it is placedl in a suitable impregnatingair-tight receptacle which is preferably heated and in which it4 is'dried under vacuum, both the moisture and the air being removed fromthe' interior and the surface of the unit andai; a tem. perature thatprevents deteriorationof the insulating material which goes to makeupthe unit.

When the unit is thoroughly vdried and I While under vacuum,- a h otliqu1d insulating compound is admitted into the 'vacuum chamber, whichnow becomes the impregnating chamber. The moisture and air having beenremoved from the pores of the insulat-- ing fabricormaterial, thiscompound penetrates into the innermost parts of t2 e same and into allvacant spaces throughout the. unit. After the compound has covered Vtheunit, compressed air is yadmitted to' the chamber above the surface ofthe compound and forces the same into'every-interstce and pore in theunit. After the, unit is removed from the chamber, the compound coolsand hardens.

I- have not illustrated .the Ameans for treat-l ing the unit winding, asthose acquainted with the art of making" magnets will readily'understand how to'fconstructfsuch means;

assuch means are well-knownrto those acquainted'A with .the art, theEmil Passburg system being specially adapted to the purpose; and as themagnet frame or casing may be lemployed as the vacuum andimpregnatingclntmber, when connected to suit* able pu"ps'and a tankcontaining the hot liquid impregnating material. Even if the windlngwere not subjected to a vacuum, the passages in the plates a,7 would aidmaterially in causing the insulating compound to pass to the interior ofthe winning.

The spacers or plates may be variously constructed to provide passagesleading to the interior of the Winding; and these passages may bevariously shaped and arranged.

I elaiml. ln a magnetwinding, two or more superposed vinding-sections,each composed of a fiat spiral having` a plurality of convolutions, andinsulating spacing means between adjacent Winding sections, said meanshaving passages therein leading to the eX- terior or' the winding so asto lead moisture and air from between the successive convolutions ofeach sectionand `to"`ad1nit insulating compound between the saidconvolutions. For a magnet-winding havingitwo or i more superposedwinding-sections5 insulating spacing means between adjacent sections,there being passages in each spacing means, b which a fluid insulatinmaterial may be introduced into the interlor of the winding,- or air andmoisture may be eX- tracted therefrom, or both.

Signed at Cleveland Ohio, this 11th day of May, 1910.

ARTHUR C. EASTWOOD.

Witnesses:

W. M. Dumm, H. S. RICHARDSON.

